133181 has 4 divisors (see below), whose sum is σ = 134652. Its totient is φ = 131712.

The previous prime is 133169. The next prime is 133183. The reversal of 133181 is 181331.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 181331 = 43 ⋅4217.

It can be written as a sum of positive squares in 2 ways, for example, as 105625 + 27556 = 325^2 + 166^2 .

It is a cyclic number.

It is not a de Polignac number, because 133181 - 2⁶ = 133117 is a prime.

It is a super-2 number, since 2×133181² = 35474357522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 590 + ... + 783.

It is an arithmetic number, because the mean of its divisors is an integer number (33663).

2¹³³¹⁸¹ is an apocalyptic number.

It is an amenable number.

133181 is a deficient number, since it is larger than the sum of its proper divisors (1471).

133181 is an equidigital number, since it uses as much as digits as its factorization.

133181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1470.

The product of its digits is 72, while the sum is 17.

The square root of 133181 is about 364.9397210499. The cubic root of 133181 is about 51.0678323338.

The spelling of 133181 in words is "one hundred thirty-three thousand, one hundred eighty-one".